Many consumers are unaware of the costs associated to use a credit or debit card on the business end. Even if we have cash in the wallet, customers opt for the credit card out of simplicity or habit. For coffeeshops in particular, the fees make up a significant portion of our many 'microtransactions.' How do you encourage customers to use cash when possible while still playing in the legal framework of the card companies (ie, not having a minimum buy) and not alienating customers who don't have cash?

You should read your contract with your processor before setting a minimum purchase amount. Most have a stipulation that forbids you from doing this, on occasion you get a customer who takes exception with your decision.

Nothing worse than an obnoxious customer with an axe to grind....except an obnoxious customer with an axe to grind who is correct.

Now that retail makes up a very small portion of our sales I have taken to telling people, just pay me later with cash or check. Since all we really get are regulars it works, and it comes across as goodwill.